Determination of sputum eosinophil count and serum absolute eosinophil count in patients with bronchial asthma and its correlation with disease severity and response to treatment

BACKGROUND: Sputum eosinophils can be used to assess severity of disease and response to treatment in bronchial asthma. Eosinophilic inflammation in the airways can also be marked by blood eosinophilia. In this study, we tried to determine the sputum eosinophil count and serum absolute eosinophil count in patients with asthma and correlate them with disease severity and treatment response. MATERIALS AND METHODS: It was a cross-sectional intervention study including all consecutive cases with a diagnosis of bronchial asthma based on spirometry and clinical history. An induced sputum sample and blood were sent for eosinophil count to the laboratory. All the patients were started on inhaled corticosteroids and followed up at the end of 1 month with spirometry, sputum eosinophil count and AEC. Statistical Package for the Social Sciences for Windows v20.0 (IBM SPSS Corp.; Armonk, NY, USA) was used for statistical analysis. RESULTS: There was no significant difference in the mean sputum eosinophil count (%) in mild, moderate and severe disease (f = 0.24; P = 0.79) or in AEC (f = 1.48; P = 0.24). At follow-up, all patients with moderate and severe disease showed significant improvement in FEV1 (P = 0.0001). The mean sputum eosinophil count and AEC (%) in the three subgroups was also seen to decrease at the end of the follow-up period (f = 0.08; P = 0.9 and f = 2.75; P = 0.07, respectively). CONCLUSION: Sputum eosinophils and AEC are important markers of airway inflammation. All our patients showed improvement in FEV1, sputum eosinophil count and AEC after 1 month of treatment thus confirming the role of ICS in the treatment of eosinophilic asthma.